# Use of a non-Schedule I drug or substance in another 21 CFR part 1308 Schedule — Medical conditions that disqualify a commercial driver under 49 CFR 391.41

For Use of a non-Schedule I drug or substance in another 21 CFR part 1308 Schedule, standard, as the regulation states it is (ii) Does not use any non-Schedule I drug or substance that is identified in the other Schedules in 21 CFR part 1308 except when the use is prescribed by a licensed medical practitioner, as defined in § 382.107 of this chapter , who is familiar with the driver's medical history and has advised the driver that the substance will not adversely affect the driver's ability to safely operate a commercial motor vehicle; and; paragraph is (b)(12)(ii); regulation section is 49 CFR 391.41, recorded from its source on 2026-08-31; source re-checked 2026-09-15.

- **Disqualifying condition or standard:** Use of a non-Schedule I drug or substance in another 21 CFR part 1308 Schedule _(our reading, not quoted from the source)_
- **Standard, as the regulation states it:** (ii) Does not use any non-Schedule I drug or substance that is identified in the other Schedules in 21 CFR part 1308 except when the use is prescribed by a licensed medical practitioner, as defined in § 382.107 of this chapter , who is familiar with the driver's medical history and has advised the driver that the substance will not adversely affect the driver's ability to safely operate a commercial motor vehicle; and _(verified: appears in the quote below)_
- **Paragraph:** (b)(12)(ii) _(our reading, not quoted from the source)_
- **Regulation section:** 49 CFR 391.41

## What the source says

> (ii) Does not use any non-Schedule I drug or substance that is identified in the other Schedules in 21 CFR part 1308 except when the use is prescribed by a licensed medical practitioner, as defined in § 382.107 of this chapter , who is familiar with the driver's medical history and has advised the driver that the substance will not adversely affect the driver's ability to safely operate a commercial motor vehicle; and

## Source

- https://www.ecfr.gov/current/title-49/subtitle-B/chapter-III/subchapter-B/part-391/subpart-E/section-391.41

Last verified: 2026-09-15. Review by: 2027-08-31.
Part of [Medical conditions that disqualify a commercial driver under 49 CFR 391.41](https://referencesource.org/dot-cdl-medical-disqualifying-conditions/).